What is the long posterior ciliary artery?

What is the long posterior ciliary artery?

The long posterior ciliary arteries are arteries of the head arising, together with the other ciliary arteries, from the ophthalmic artery. There are two in each eye.

What does posterior ciliary artery supply?

The posterior ciliary artery (PCA) circulation is the main source of blood supply to the optic nerve head (ONH), and it also supplies the choroid up to the equator, the retinal pigment epithelium (RPE), the outer 130 m of retina (and, when a cilioretinal artery is present, the entire thickness of the retina in that …

What is a ciliary artery?

The short ciliary arteries pierce the sclera near the optic nerve and directly supply the choroidal vessels that nourish the outer one-third of the retina. They form the anastamotic circle of Zinn and Haller, adjacent to the optic nerve that feeds the optic disc.

What does short posterior ciliary artery supply?

The short posterior ciliary arteries supply the choroid and parts of the optic nerve. The two long posterior ciliary arteries supply the ciliary body and anastomose with each other and with the anterior ciliary arteries to form the major arterial circle of the iris.

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What does the long ciliary nerve supply?

The long ciliary nerves provide sensory innervation to the eyeball, including the cornea. In addition, they contain sympathetic fibers from the superior cervical ganglion to the dilator pupillae muscle.

How many posterior ciliary arteries are there?

The two long posterior ciliary arteries arise from the ophthalmic artery and after piercing the sclera near the optic nerve head they travel forward in the choroid in the medial and lateral horizontal plane and divide in the ciliary body before anastomosing with anterior ciliary branches, thus forming the major ‘circle …

What artery supplies the macula?

Causes. The favored explanation for why the center visual field is preserved after large hemispheric lesions is that the macular regions of the cortex have a double vascular supply from the middle cerebral artery (MCA) and the posterior cerebral artery (PCA).

Where is the uveal tract located?

the eye The middle layer of the wall of the eye.

Where is ciliary muscle?

The ciliary muscle is elongated, triangular in shape, and located beneath the anterior sclera just posterior to the limbus. The shortest side of the triangular region faces anterior-inward and it is to this region of the ciliary body that the base of the iris inserts.

Where do the ciliary arteries come from?

The anterior ciliary arteries are seven small arteries in each eye-socket that supply the conjunctiva, sclera and the rectus muscles. They are derived from the muscular branches of the ophthalmic artery.

What is blood supply of ciliary body?

Traditional views hold that the vasculature of the ciliary body is supplied by the anterior ciliary arteries and the long posterior ciliary arteries, forming the major arterial circle near the root of the iris, wherefrom branches supply the iris, ciliary body and the anterior choroid.

What’s the main artery called?

aorta The largest artery is the aorta, the main high-pressure pipeline connected to the heart’s left ventricle. The aorta branches into a network of smaller arteries that extend throughout the body. The arteries’ smaller branches are called arterioles and capillaries.

What does the short ciliary nerve do?

The short ciliary nerves are a group of nerves that branch from the nasociliary nerve in the intraconal space via the ciliary ganglion. Along with the long ciliary nerves, they supply sensation to the entire globe excluding the conjunctiva.

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What is circle of Zinn Haller?

The circle of ZinnHaller (CZH) is known to be an intrascleral arteriolar anastomosis derived from medial and lateral paraoptic short posterior ciliary arteries (SPCAs). The significance of this arterial circle in supplying the anterior optic nerve and peripapillary region has been the subject of controversy.

What is in the circle of Willis?

The Circle of Willis is the joining area of several arteries at the bottom (inferior) side of the brain. At the Circle of Willis, the internal carotid arteries branch into smaller arteries that supply oxygenated blood to over 80% of the cerebrum.

How many long ciliary nerves are there?

There are 2-3 long ciliary nerves which carry somatosensory fibers as well as sympathetic fibers from the adjacent ICA, each entering the posterior globe separately to supply the dilator pupillae and sensation to the cornea.

What does the posterior ethmoidal nerve innervate?

It passes through the posterior ethmoidal foramen, with the posterior ethmoidal artery. It carries sensory information from the sphenoid sinus and posterior ethmoidal air cells. …

Posterior ethmoidal nerve
From nasociliary nerve
Innervates sphenoidal sinus, ethmoidal sinus
Latin nervus ethmoidalis posterior

What is the ciliary ganglion?

Ciliary ganglion is a peripheral parasympathetic ganglion. It is situated near the apex of orbit between the optic nerve and lateral rectus muscle. It is related medially to the ophthalmic artery and laterally to the lateral rectus muscle.

What is white of eye?

Sclera: the white of your eye. Conjunctiva: a thin layer of tissue that covers the entire front of your eye, except for the cornea.

What is a Cilioretinal artery?

Cilioretinal arteries belong to the posterior ciliary artery system. They arise either directly from the choroid or from one of the posterior ciliary arteries, providing additional or alternative blood supply to the retina. Usual location is the edge of the optic nerve head, most commonly on the temporal side.

What is choroidal?

The choroid (pronounced CORE-oyd) is a spongy layer of blood vessels that lines the back wall of the eye between the retina and the sclera (or the white part of the eye). It plays an important role in delivering oxygen and nutrients to the outer half of the retina.

What is the difference between the fovea and the macula?

Fovea: The pit or depression at the center of the macula that provides greatest visual acuity. … Macula: The portion of eye at the center of the retina that processes sharp, clear, straight-ahead vision.

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Why macula is spared?

For patients, macular sparing remains important because it mitigates the impact of hemianopia and preserves the ability to read fluently.

How is Alexia diagnosed?

Diagnosis is based on the symptom of not being able to read, but the patient still maintains visual acuity and the ability to write. Patients often have right homonymous hemianopia due to left occipital lobe involvement. Neuropsychometric testing may also be used to diagnose alexia without agraphia.

What is the function of uveal tract?

It is the source of blood flow to the ocular tissues. It is the source of aqueous humour (fluid that fills the inside of the eye) and maintenance of intraocular pressure. It constitutes the blood-aqueous barrier and prevents undesired blood products from reaching the eye.

What is difference between choroid and uvea?

is that choroid is (anatomy) the vascular layer of the eye lying between the retina and the sclera while uvea is (anatomy) the middle of the three concentric layers that make up the eye; it is pigmented and vascular, and comprises the choroid, the ciliary body, and the iris.

Which part of the eye is uveal?

The uvea is the middle layer of the eye. It lies beneath the white part of the eye (the sclera). It is made of the iris, ciliary body, and choroid. These structures control many eye functions, including adjusting to different levels of light or distances of objects.

What are the two main functions of the ciliary body?

The ciliary body has three functions: accommodation, aqueous humor production and resorption, and maintenance of the lens zonules for the purpose of anchoring the lens in place.

What Innervates ciliary body?

Innervation. The major innervation is provided by ciliary nerve branches (third cranial nerve-oculomotor), forming a rich parasympathetic plexus.

What is the role of the ciliary muscle?

Ciliary muscle: A circular muscle that relaxes or tightens the zonules to enable the lens to change shape for focusing. The zonules are fibers that hold the lens suspended in position and enable it to change shape during accommodation.